ck_swlock(3) | Library Functions Manual | ck_swlock(3) |
NAME
ck_swlock_init
,
ck_swlock_write_latch
,
ck_swlock_write_unlatch
,
ck_swlock_write_lock
,
ck_swlock_write_unlock
,
ck_swlock_write_trylock
,
ck_swlock_write_downgrade
,
ck_swlock_locked_writer
,
ck_swlock_read_lock
,
ck_swlock_read_trylock
,
ck_swlock_read_unlock
,
ck_swlock_locked_reader
—
centralized copy-safe write-biased single-writer read-write
locks
LIBRARY
Concurrency Kit (libck, -lck)
SYNOPSIS
#include
<ck_swlock.h>
ck_swlock_t lock =
CK_SWLOCK_INITIALIZER;
void
ck_swlock_init
(ck_swlock_t
*lock);
void
ck_swlock_write_lock
(ck_swlock_t
*lock);
void
ck_swlock_write_unlock
(ck_swlock_t
*lock);
void
ck_swlatch_write_latch
(ck_swlatch_t
*latch);
void
ck_swlatch_write_unlatch
(ck_swlatch_t
*latch);
bool
ck_swlock_write_trylock
(ck_swlock_t
*lock);
bool
ck_swlock_write_downgrade
(ck_swlock_t
*lock);
bool
ck_swlock_locked_writer
(ck_swlock_t
*lock);
void
ck_swlock_read_lock
(ck_swlock_t
*lock);
bool
ck_swlock_read_trylock
(ck_swlock_t
*lock);
void
ck_swlock_read_unlock
(ck_swlock_t
*lock);
bool
ck_swlock_locked_reader
(ck_swlock_t
*lock);
DESCRIPTION
This is a centralized write-biased single-writer reader-writer lock. It requires half the space that ck_rwlock does and has a low latency fast path. The lock supports latch and unlatch operations that allow it to be used in a copy-safe manner (reader-bits may be over-written safely).
EXAMPLE
#include <ck_swlock.h> static ck_swlock_t lock = CK_SWLOCK_INITIALIZER; static void reader(void) { for (;;) { ck_swlock_read_lock(&lock); /* Read-side critical section. */ ck_swlock_read_unlock(&lock); if (ck_swlock_read_trylock(&lock) == true) { /* Read-side critical section. */ ck_swlock_read_unlock(&lock); } } return; } static void writer(void) { ck_swlock_t contrived; for (;;) { ck_swlock_write_lock(&lock); /* Write-side critical section. */ ck_swlock_write_unlock(&lock); if (ck_swlock_write_trylock(&lock) == true) { /* Write-side critical section. */ ck_swlock_write_unlock(&lock); } ck_swlock_write_latch(&lock); /* Write-side critical section. */ /* This is safe to do with-in a latch. */ contrived = lock; lock = contrived; ck_swlock_write_unlatch(&lock); } return; }
SEE ALSO
ck_brlock(3), ck_elide(3), ck_pflock(3), ck_rwlock(3), ck_tflock(3)
Additional information available at http://concurrencykit.org/
April 22, 2014. |